Rubber sheet jointing apparatus and method

ABSTRACT

A rubber sheet jointing apparatus is provided with first holding means for releasably holding a joint end portion of one of two rubber sheets, second holding means provided movably relative to the first holding means for releasably holding a joint end portion of the other of the two rubber sheets, and operating means for pressure-contacting the end surfaces of the two rubber sheets respectively held by the first and second holding means by moving the second holding means relative to the first holding means. Mutually facing surfaces of the first and second holding means are respectively provided with holder portions which are formed as rugged portions each taking a comb tooth shape and which are able to partly overlap to mesh with each other.

INCORPORATION BY REFERENCE

This application is a divisional of U.S. Ser. No. 11/443,183, filed May31, 2006, and is based on and claims priority under 35 U.S.C. 119 withrespect to Japanese Applications No. 2005-165041 filed on Jun. 6, 2005and No. 2005-226908 filed on Aug. 4, 2005. The entire contents of thesethree applications are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention:

The present invention relates to a rubber sheet joining apparatus andmethod for joining the end surfaces of one or two rubber sheets witheach other by butt joint. In particular, it relates to a rubber sheetjoining apparatus and method capable of manufacturing a jointed planerubber sheet or a round or endless rubber band easily and efficientlywithout making any bulge at the jointed portion thereof.

2. Discussion of the Related Art:

Generally, for vehicular tires, inner liners which are composite rubbersheets made from rubber only and body or carcass plies, belts and thelike which are rubber sheets reinforced by fibers or steel cords areoften used by jointing end surfaces of rubber sheet strips. For example,the rubber sheet for a body ply, a belt or the like having apredetermined length can be manufactured by making by a calendar rollingmachine a roll of a long rubber textile or cloth having numerous cordsembedded in the rubber layer, then by uncoiling and cutting the roll ofthe long rubber cloth which has the cords arranged parallel in thelongitudinal direction thereof, to those sheet strips of the lengthcorresponding to the width of the body ply or the belt which widthdepends on the kind and dimension of the tire to be manufactured, andfurther, by mutually jointing the end edges parallel to the cords ofthose rubber sheet stripes so cut.

Used generally for jointing end edges of two adjoining sheets are twomethods called “lap joint” and “butt joint”. The lap joint can beperformed by lapping an end edge of a second sheet on an end edge of afirst sheet and then, by applying a pressure on a jointed area includingthe lapped area.

In the lap joint method, since the thickness of the rubber sheet at thelapped joint area becomes as twice the thickness of other areas, doubledare not only the thickness of the rubber sheet, but also the number ofthe reinforcing cords in the case of a fiber or steel cord reinforcedrubber sheet. Thus, the thickness of the jointed rubber sheet dose notbecome uniform and the difference in rigidity becomes large, so that theuniformity of the tire is degraded. For this reason, the use of the lapjoint method tends to decrease these days.

On the other hand, the butt joint can be performed by thrusting the endedge of one sheet against the end edge of the other sheet and then, bypressuring them to be firmly jointed by mechanical or physical means.Thus, a bulge is generated at the jointed portion.

That is, as described in Japanese Unexamined Published PatentApplication No. 2004-142219, since the both end edges of first andsecond sheets are jointed as being drawn to come closer to each other bya pair of rollers each taking a bevel wheel shape, the bulge isgenerated on the jointed portion.

In order to level out the bulge on the jointed portion, the technologydescribed in the foregoing Japanese application is designed to heightenthe flatness at the jointed portion by adding as a step subsequent tothe sheet jointing a leveling or smoothening step of pressing down thejointed portion by upper and lower leveling plates including warmingmeans with the jointed portion being put therebetween from upper andlower sides.

However, in the technology described in the foregoing Japaneseapplication, the flatness on the jointed portion is obtained bychemically changing the quality of the rubber by the use of the upperand lower leveling plates including the warming means. Thus, the jointedportion and other portions of the sheet become the same in thickness,but different in quality. Therefore, where tires are manufactured usingsheets each jointed by the foregoing jointing method, it results that aportion which is not uniform in physical property with other portions ispresent on the circumference of the tire, and this causes an obstructionin enhancing the tire quality. In addition, the addition of thesmoothening step causes not only an increase in the cost of themanufacturing facilities, but also an elongation in the manufacturingcycle time.

Further, as described in Japanese Unexamined Published PatentApplication No. 2002-11805, there has also been known a jointingapparatus and method for butt-jointing the circumferential opposite endportions of an unvulcanized rubber sheet blank such as carcass or bodyply used as tire component blank or the like on a shaping drum. In theapparatus and method described in the Japanese application, a belt-likerubber blank cut to a predetermined length is wound on thecircumferential surface of the shaping drum to cling thereto withjointing portions of the shaping drum held opened, and joint endportions of the belt-like rubber blank are drawn toward each other to betemporarily jointed by closing or diametrically contracting the shapingdrum, in which state the joint end portions are pressure-jointed by apair of rollers each taking a bevel wheel shape.

In the last mentioned apparatus and method, since the joint end portionsof the belt-like shape rubber blank are jointed as they are made by therollers of the bevel wheel shape to come close to each other, itnecessarily results that the jointed portion has a bulge thereon and isdegraded in flatness. Accordingly, in order to level out the bulge onthe jointed portion, it becomes necessary to heighten the flatness atthe jointed portion by adding as a step subsequent to the sheet jointinga smoothening step of pressing down the jointed portion by levelingplates including warming means with the jointed portion being puttherebetween from upper and lower sides, as described in the firstmentioned Japanese application.

As described above, in the last mentioned apparatus and method, in orderto level out the bulge on the jointed portion, it is required to improvethe flatness by chemically degenerating the rubber by the use of theleveling plates including warming means, as described in the firstmentioned Japanese application. Accordingly, where tires aremanufactured using carcass or body plies each jointed by the lastmentioned jointing apparatus and method, each tire would have at thecircumferential portion thereof a portion which lacks uniformity becauseof being different in physical property, thereby making an obstructionin improving the tire quality. In addition, the addition of thesmoothening step undesirably causes not only an increase in the cost fortire manufacturing facilities but also an elongation in themanufacturing cycle time.

SUMMARY OF THE INVENTION

It is therefore a primary object of the present invention to provide animproved jointing apparatus and method for jointing end surfaces of twojoint end portions of at least one rubber sheet to have a jointedportion which does not have any bulge thereon and which is uniform inthickness as well as in quality.

Another object of the present invention is to provide an improvedjointing apparatus and method of the character set forth above which isparticularly designed for manufacturing plane rubber sheet blanks.

A further object of the present invention is to provide an improvedjointing apparatus and method of the character set forth above which isparticularly designed for manufacturing round or endless rubber sheetblanks.

A still further object of the present invention is to provide animproved jointing apparatus and method of the character set forth abovewhich is particularly designed for continuously performing the jointingof a plurality of rubber sheet strips to manufacture an elongated rubbersheet batch and the jointing of opposite end portions of the elongatedrubber sheet batch to manufacture a round or endless rubber band withina single rubber sheet joining apparatus.

According to one aspect of the present invention, there is provided arubber sheet jointing apparatus for jointing end surfaces of two jointend portions of at least one rubber sheet by butt joint. The apparatuscomprises first holding means for releasably holding one of the twojoint end portions; second holding means provided movably relative tothe first holding means for releasably holding the other of the twojoint end portions; and operating means for pressure-contacting endsurfaces of the two joint end portions respectively held by the firstand second holding means by effecting relative movement between thefirst and second holding means. Mutually facing surfaces of the firstand second holding means are respectively provided with holder portionswhich are able to overlap to mesh with each other.

With this construction, since the holder portions which are able tooverlap to mesh with each other are provided on the mutually facingsurfaces of the first and second holding means for respectively holdingthe two joint end portions to be jointed with each other, the jointingof the joint end surfaces with each other can be realized with theentire parts of the two joint end portions being held steadily. Thus,even when the two joint end portions of the at least one rubber sheetare pressure-joined with a strong pressuring force, any bulge can beprevented from occurring on the jointed portion. Therefore, it can berealized to easily manufacture a plane rubber sheet blank or a roundrubber sheet blank which is uniform in thickness and excellent inflatness at the jointed portion. In addition, because no heat is appliedto the rubber sheet, the same does not deteriorate in quality, so thatit can be realized to easily obtain the plane rubber sheet blank or around rubber sheet which is uniform also in quality at the jointedportion.

According to another or second aspect of the present invention, there isprovided a rubber sheet jointing method of jointing end surfaces of twojoint end portions of at least one rubber sheet by butt joint. Themethod comprises the steps of providing first and second holding meanswhich are able to overlap to mesh with each other at mutually facingsurfaces thereof; making one of the first and second holding means holdone of the two joint end portions and making the other of the first andsecond holding means hold the other of the two joint end portions; andrelatively moving the first and second holding means to a position wherethe first holding means partly overlap with the second holding meansthrough the meshing engagement at the mutually facing surfaces of thefirst and second holding means, to joint through pressuring contact theend surface of one of the two joint end portions being held by the firstholding means with the other joint end portion being held by the secondholding means.

With the construction in the second aspect, the first holding means forholding one of the two joint end portions and the second holding meansfor holding the other of the two joint end portions are relatively movedto the position where they overlap with each other, to joint the twojoint end portions of at least one rubber sheet. Thus, even when the twojoint end portions are pressure-joined with a strong pressuring force,any bulge can be prevented from occurring on the jointed portion. Thismakes it unnecessary to perform a leveling or smoothening step ofrolling or leveling any bulge which would otherwise be formed on thejointed portion after the jointing step. Accordingly, it can be realizedto efficiently manufacture a plane rubber sheet blank or a round orendless rubber sheet blank which is uniform in thickness and excellentin flatness at the jointed portion.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects and many of the attendant advantages ofthe present invention may readily be appreciated as the same becomesbetter understood by reference to the preferred embodiments of thepresent invention when considered in connection with the accompanyingdrawings, wherein like reference numerals designate the same orcorresponding parts throughout several views, and in which:

FIG. 1 is a plan view of a rubber sheet jointing apparatus in a firstembodiment according to the present invention;

FIG. 2 is an enlarged side view of the apparatus as viewed in thedirection A in FIG. 1;

FIG. 3 is an enlarged elevational view of the apparatus as viewed in thedirection B in FIG. 2;

FIG. 4 is a fragmentary view showing a portion C shown in FIG. 2 indetail in an exaggerated scale;

FIG. 5 is a fragmentary view taken along a line D-D in FIG. 4 forshowing rugged portions which are able to mesh with each other, in afurther exaggerated scale;

FIG. 6 is a view similar to FIG. 2 showing the apparatus in a state thata first rubber sheet has been supplied;

FIG. 7 is a view similar to FIG. 2 showing the apparatus in anotherstate that the apparatus holds two rubber sheets;

FIG. 8 is a view similar to FIG. 2 showing the apparatus in stillanother state that the two rubber sheets have been jointed;

FIG. 9 is a view similar to FIG. 2 showing the apparatus in a furtherstate that the jointed rubber sheet is sent out by a predetermineddistance;

FIG. 10 is an explanatory view showing a feeding state of a ribbon;

FIG. 11 is a plan view of a rubber sheet jointing apparatus in a secondembodiment according to the present invention;

FIG. 12 is an explanatory view showing a feeding state of a ribbon inthe second embodiment;

FIG. 13 is a plan view of a rubber sheet jointing apparatus in a thirdembodiment according to the present invention;

FIG. 14 is a side view of the apparatus shown in FIG. 13;

FIG. 15 is a front view of a rubber sheet jointing device incorporatedin the apparatus;

FIG. 16 is a side view of the rubber sheet jointing device as viewed inthe direction A in FIG. 15;

FIG. 17 is a longitudinal sectional view of a shaping drum taken alongthe line B-B in FIG. 15;

FIG. 18 is a plan view of a part of the external surface of the shapingdrum as viewed in the direction C in FIG. 16;

FIG. 19 is a bottom view of a part of the rubber sheet jointing deviceas viewed in the direction D in FIG. 15;

FIG. 20 is a sectional view of the rubber sheet jointing device takenalong the line E-E in FIG. 15;

FIG. 21 is a fragmentary view showing the operational state of a part ofthe rubber sheet jointing device in an exaggerated scale;

FIG. 22 is a plan view of a rubber sheet jointing apparatus in a fourthembodiment according to the present invention;

FIG. 23 is an enlarged side view of the apparatus as viewed in thedirection E in FIG. 22;

FIG. 24 is a plan view showing hands of a robot in the fourth embodimentaccording to the present invention;

FIG. 25 is a rear view of the robot hands as viewed in the direction Fin FIG. 24; and

FIG. 26 is a side view similar to that shown in FIG. 23 with theapparatus being in a different state of operation.

DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

(First Embodiment)

Hereinafter, with reference to the accompanying drawings, descriptionwill be made regarding a first embodiment wherein the present inventionis practiced for manufacturing fiber-reinforced plane rubber sheetblanks for tire body plies. For convenience in description, a verticaldirection, a left-right horizontal direction and a front-rear horizontaldirection in FIG. 2 will be referred to as a Z-axis direction, a Y-axisdirection and an X-axis direction respectively, and the left and rightin FIG. 2 will be referred to as the front side and the rear side in theY-axis direction, respectively.

Referring now to FIGS. 1 through 3, a rubber sheet jointing apparatus 10for jointing the end surfaces of two rubber sheets S is arranged at abutt joint station 2 st. The jointing apparatus 10 is provided with asupport table 12, which is horizontally arranged on the factory floorthrough leg portions 11 thereof. The support table 12 has a pair ofsupport pillars 13, 14 upstanding with a predetermined spacetherebetween. The upper ends and the lower ends of the pair of supportpillars 13, 14 are connected with respective crossbeams 15, 16, wherebya fixed frame 17 is constituted by the support pillars 13, 14 and thecrossbeams 15, 16.

Mounting bases 19, 20 each extending in the X-axis direction are fixedrespectively on the crossbeams 15, 16 of the fixed frame 17, and themounting bases 19, 20 are respectively provided with first holding means21 for holding one of two rubber sheets S which are to be jointed witheach other, and a second holding means 22 which is movable relative tothe first holding means 21 in the horizontal Y-direction while holdingthe other of the two rubber sheets S.

The first holding means 21 is provided with a pair of first holders 23,24 which are movable to and from each other in the vertical direction.The pair of first holders 23, 24 are vertically movably guidedrespectively along upper and lower linear guides 25, 26 arranged in thevertical direction and are vertically opened and closed by firstcylinder actuators 29, 30 in a synchronous relation.

That is, guide blocks 25 b for the upper linear guides 25 are arrangedat the opposite ends in the X-axis direction of the upper mounting base19, and the guide blocks 25 b vertical slidably guide rails 25 arespectively. The rails 25 a attach thereto connection blocks 27, whichare connected respectively to the opposite end portions of the firstholder 23 on the upper side.

Similarly, guide blocks 26 b for the lower linear guides 26 are arrangedat the opposite ends in the X-axis direction of the lower mounting base20, and the guide blocks 26 b vertical slidably guide rails 26 arespectively. The rails 26 a attach thereto connection blocks 28, whichare connected respectively to the opposite end portions of the firstholder 24 on the lower side.

The first cylinder actuators 29, 30 are arranged respectively at centerportions in the X-axis direction of the mounting bases 19, 20, andpiston rods of the first cylinder actuators 29, 30 are connectedrespectively to the upper end of the first holder 23 on the upper sideand the lower end of the first holder 24 on the lower side. Thus, thepair of first holders 23, 24 can be opened and closed vertically by thefirst cylinder actuators 29, 30.

As shown in FIGS. 4 and 5 in detail, rugged portions 31 a, 32 a eachtaking a comb tooth shape of a predetermined depth are formed atrespective end portions (the left end portions as viewed in FIG. 2) ofholder portions 31, 32 which are defined as holder ends of the pair offirst holders 23, 24, and are able to partly overlap with those of apair of second holders, as referred to later. Mutually facing ends inthe vertical direction of the holder portions 31, 32 cooperate to holdthe joint end portion of the rubber sheet S at a position retracted byan amount L1 from the end surfaces of the rugged portions 31 a, 32 a.The predetermined depth of the rugged portions 31 a, 32 a is set to bedeeper than the amount L1, as referred to later in detail. Further, asshown in FIG. 4, the mutually facing surfaces at which the holderportions 31, 32 are brought into contact with the rubber sheet S haveformed thereon wave claws 31 b, 32 b such as, e.g., saw tooth claws of aminute height which bite the upper and lower surfaces of the rubbersheet S, so that the rubber sheet S does not retract relative to theholder portions 31, 32 during the jointing operation.

The horizontal lengths of the holder portions 31, 32 in the X-axisdirection is designed to be longer than the length LB (refer to FIG. 10)of the rubber sheet S, and when the operations of the first cylinderactuators 29, 30 cause the first holders 23, 24 to come closer to eachother, the holder portions 31, 32 can hold the rubber sheet Stherebetween over the entire length of the rubber sheet S.

On the other hand, the second holding means 22 is provided with a pairof second holders 41, 42 which are vertically movable to and from eachother. The pair of second holders 41, 42 are connected to the connectionblocks 27, 28 through upper linear guides 43 and lower linear guides 44which are arranged horizontally in the Y-axis direction. Therefore, thepair of second holders 41, 42 can be opened or closed bodily with theopening or closing motion of the pair of first holders 23, 24.

That is, the pair of second holders 41, 42 are provided on the rails 43a, 44 a of the upper and lower linear guides 43, 44 to face the firstholders 23, 24 in the Y-axis direction, respectively. The rails 43 a, 44a are guided by the guide blocks 43 b, 44 b provided on the connectionblocks 27, 28, to be slidable in the horizontal Y-axis direction.

The connection blocks 27, 28 are provided with second cylinder actuators47, 48, whose piston rods are connected to the pair of second holders41, 42. Therefore, the pair of second holders 41, 42 are bodily moved inthe horizontal direction by the synchronous motions of the secondcylinder actuators 47, 48, so that the second holders 41, 42 are movedrelative to the first holders 23, 24 in the Y-axis direction. The secondcylinder actuators 47, 48 constitute operating means in the claimedinvention.

As shown in FIGS. 4 and 5 in detail, rugged portions 45 a, 46 a eachtaking a comb tooth shape of the aforementioned predetermined depth areformed at end portions (the right end portions as viewed in FIG. 2) ofholder portions 45, 46 which are defined as holder ends of the pair ofsecond holders 41, 42 respectively facing the first holders 23, 24. Therugged portions 45 a, 46 a are able to partly overlap with those of thepair of first holders 23, 24. Mutually facing ends in the verticaldirection of the holder portions 45, 46 cooperate to hold the joint endportion of another rubber sheet S (which will be referred to as “secondrubber sheet S” only for the sake of distinction from the rubber sheet Sbeing held by the first holders 23, 24) to be jointed with the firstmentioned rubber sheet S, at a position retracted by the aforementionedamount L1 from the end surfaces of the rugged portions 45 a, 46 a. Thepredetermined depth of the rugged portions 45 a, 46 a is set to bedeeper than the amount L1. Further, as shown in FIG. 4, the mutuallyfacing surfaces at which the holder portions 45, 46 are brought intocontact with the second rubber sheet S have formed thereon wave claws 45b, 46 b such as, e.g., saw tooth claws of the aforementioned minuteheight which bite the upper and lower surfaces of the second rubbersheet S, so that the second rubber sheet S does not retract relative tothe holder portions 45, 46 during the jointing operation.

As best shown in FIG. 5, the rugged portions 45 a, 46 a formed on theside of the pair of second holders 41, 42 are arranged to face theirconcave portions with the convex portions of the rugged portions 31 a,32 a formed on the side of the pair of first holders 23, 24, so that asmentioned earlier, the rugged portions 45 a, 46 a can complementarily bemeshed respectively with the rugged portions 31 a, 32 a. Therefore, thefirst holders 23, 24 and the second holders 41, 42 partly overlap witheach other through intermeshing of the comb-tooth shape rugged portions31 a, 32 a with the comb-tooth shape rugged portions 45 a, 46 a. Thehorizontal length of the holder portions 45, 46 in the X-axis directionis also designed to be longer than the aforementioned length LB of therubber sheet S, so that the holder portions 45, 46 can hold the secondrubber sheet S therebetween over the entire length of the second rubbersheet S.

Rails 51 a of parallel linear guides 51 (one only shown in FIG. 2)extending in the Y-axis direction are fixed on the support table 12behind the fixed frame 17, and a movable table 52 is guided on the rails51 a through guide blocks 51 b of the liner guides 51 to be movable inthe Y-axis direction. The movable table 52 has a vertical frame 53upright therefrom, on which feeding means 54 is provided for holding andfeeding the rubber sheet S (i.e., one rubber sheet or a batch of two ormore jointed rubber sheets) by a predetermined amount whenever operated.

The feeding means 54 is provided with a pair of third holders 55, 56which are vertically movable to and from each other. The pair of thirdholders 55, 56 are respectively connected to third cylinder actuators57, 58 mounted on the vertical frame 53 and are vertically opened andclosed by the third cylinder actuators 57, 58. The pair of third holders55, 56 pass through the fixed frame 17 and extend their ends (i.e.,their front ends) to a position where the delivery of the rubber sheet Scan be done between the first holders 23, 24 and themselves. The thirdcylinder actuators 57, 58 serve as second operation means recited in theclaimed invention.

A ball screw shaft 61 is supported under the support table 12 to berotatable about an axis parallel to the Y-axis direction and isscrew-engaged with a ball nut 62 fixed on the lower surface of themovable table 52. The ball screw shaft 61 is connected to a motor shaftof an electric motor 63 mounted on the support table 12, so that uponoperation of the electric motor 63, the movable table 52 is controllablymoved through the ball screw shaft 61 and the ball nut 62 in the Y-axisdirection.

Components which respectively movably guide and support the firstholding means 21 and the second holding means 22 are arranged to bevertically symmetrical as viewed in FIG. 3. However, in order that theconstructions of the first holding means 21 and the second holding means22 become easier to understand, FIG. 2 is drawn by omitting at the upperhalf the cylinder actuator 47 for moving the second holder 41 arrangedon the upper side and by omitting at the lower half the liner guide 26,the connection block 28, the first cylinder actuator 30 and the likewhich are provided for guiding the first holder 24 on the lower side.

As shown in FIG. 10, the foregoing rubber sheet S is made by cutting aribbon R of a predetermined width LA which is scrolled around a bobbinB, to those strips of the aforementioned predetermined length LB whichcorresponds to a ply width which is determined in dependence on thekind, size and the like of the tires to be manufactured. The cutting isperformed at right angles to the cords C embedded in each of thosestrips. The ribbon R is constituted by rubber-coating a plurality offiber cords made of, e.g., polyester. The fiber cords C are placed undera dipping process for better property of adhesiveness with rubber.Although not shown, the rubber coating of the fiber cords C can be doneby causing the fiber cords C to pass through an unvulcanized compoundrubber layer which is extruded by a small extruding machine.

As shown in FIGS. 1 and 10, a cutting station 1 st for cutting theribbon R to those strips of the predetermined length LB is arranged tobe next to the butt joint station 2 st. The cutting station 1 st isprovided with supply means 70 for holding and supplying the ribbon R fedfrom the bobbin B, to the butt joint station 2 st and cutting means 80for cutting the ribbon R to those strips of the predetermined length LBcorresponding to the ply width LB at right angles to the cords C.Rectangular or elongated rubber sheets S each having the width LA andthe length LB are made by the cutting means 80 and are successivelysupplied by the supply means 70 to the butt joint station 2 st. In thisfirst embodiment, the elongated rubber sheets S are jointed insuccession one after another at their side end edges extending in thelengthwise direction thereof, as best illustrated in FIG. 10, asdescribed hereunder.

(Operation)

The operation of the first embodiment as constructed above will bedescribed hereafter. In the following description of the operation, forbetter understanding, each rubber sheet S supplied to the second holdingmeans 22 will be called “rubber sheet strip” whereas an aggregation ofplural jointed rubber sheets S will be called “rubber sheet group orbatch”.

First of all, the end portion of the ribbon R in which the fiber cordsare embedded in a rubber layer of the predetermined width LA is led tothe cutting station 1 st and is cut by the cutting means 80 to a rubbersheet strip S of the predetermined length (the body ply width) LB whichis determined in dependence on the kind, size and the like of the tiresto be manufactured. The rubber sheet strip S cut to the predeterminedlength LB is supplied by the supply means 70 to the butt joint station 2st (refer to FIGS. 1 and 10).

When the first rubber sheet strip S is supplied to the butt jointstation 2 st with its left side portion being held by the supply means70 as viewed in FIG. 2, the electric motor 63 is driven, and therotation of the electric motor 63 controllably moves the movable table52 through the ball screw shaft 61 and the ball nut 62 from the originalposition toward the second holder means 22 in the Y-axis direction.Thus, as shown in FIG. 6, the movable table 52 is advanced to theposition where the third holders 55, 56 can hold the right side portionof the rubber sheet strip S whose left side portion is being held by thesupply means 70. In this state, the third holders 55, 56 are moved bythe third cylinder actuators 57, 58 mounted on the movable table 52 tocome close to each other, whereby the third holder 55, 56 hold the rightside portion of the first rubber sheet strip S.

Only when the very first rubber sheet strip S is supplied in this way,the third holders 55, 56 remain vacant without holding any rubber sheetstrip S and therefore, the movable table 52 is controllably moved sothat the third holders 55, 56 go to fetch the supplied rubber sheetstrip S directly.

When the right side portion of the rubber sheet strip S is held by thethird holders 55, 56, the left side portion of the rubber sheet strip Sis released from the holding by the supply means 70, in which state theelectric motor 63 is driven in a direction opposite to the foregoingoperation to retract the movable table 52 in the Y-axis direction. Themovable table 52 is retracted to the position shown in FIG. 2 where thefirst holders 23, 24 can hold the joint end portion (the left sideportion as viewed in FIG. 4) of the rubber sheet strip S whose rightside portion being still held by the third holders 55, 56. Thus, a jointend surface S1 (shown in FIG. 10) of the first rubber sheet strip S ispositioned to a position which recedes the slight amount (L1) in theY-axis direction from the end surfaces of the comb-tooth shape ruggedportions 31 a, 32 a of the first holders 23, 24.

Then, a second rubber sheet strip S cut to the predetermined length LBin the same manner as aforementioned is supplied to the butt jointstation 2 st. A joint end surface S1 (the right end surface as viewed inFIG. 4) of the second rubber sheet strip S supplied to the butt jointstation 2 st is thus placed between the second holders 41 and 42 and ispositioned to the position where it recedes by the slight amount (L1) inthe Y-axis direction from the right end surfaces of the comb-tooth shaperugged portions 45 a, 46 a of the second holders 41, 42. In this state,the first cylinder actuators 29, 30 are operated, and the first holders23, 24 are vertically moved to come close toward each other while beingguided along the linear guides 25, 25 in the Z-axis direction. Thus, theupper and lower surface of the joint end portion of the first rubbersheet strip S being held by the third holders 55, 56 are held (pinched)by the holder portions 31, 32 of the first holders 23, 24. It resultsfrom this that the first rubber sheet strip S is held by the holdingportions 31, 32 at the position where the joint end surface S1 recedesby the slight amount (L1) in the Y-axis direction from the end surfacesof the comb-tooth shape rugged portions 31 a, 32 a of the first holders23, 24, as indicated by the phantom line in FIG. 4.

As the first holders 23, 24 are vertically moved to come close to eachother, the second holders 41, 42 are vertically moved bodily with thefirst holders 23, 24 through the connection blocks 27, 28 and the secondcylinder actuators 47, 48 to come close to each other. Thus, the upperand lower surface of the joint end portion (i.e., the right end portionas viewed in FIG. 4) of the second rubber sheet strip S whose left sideportion being still held by the supply means 70 are held (pinched) bythe holder portions 45, 46 of the second holders 41, 42. Also in thiscase, the second rubber sheet strip S is held by the holder portions 45,46 at the position where the joint end surface S1 (i.e., the right endsurface) recedes by the slight amount (L1) in the Y-axis direction fromthe end surfaces of the comb-tooth shape rugged portions 45 a, 46 a ofthe second holders 41, 42, as indicated by the phantom line in FIG. 4.

When the two rubber sheet strips S are held respectively between thefirst holders 23 and 24 and between the second holders 41 and 42 asshown in FIG. 7, the third holders 55, 56 are operated to open by thethird cylinder actuators 57, 58 and the second rubber sheet strip S isreleased from the holding by the supply device 70.

Subsequently, the second cylinder actuators 47, 48 are operated, and thesecond holders 41, 42 are horizontally moved toward the first holders23, 24 while being guided by the linear guides 43, 44 in the Y-axisdirection until the rugged portions 45 a, 46 a of the comb tooth shapeformed on the second holders 41, 42 are respectively brought intocomplementary meshing with the rugged portions 31 a, 32 a of the combtooth shape formed on the first holders 23, 24. In this way, as therugged portions 45 a, 46 a of the comb tooth shape on the side of thesecond holders 41, 42 are complementarily entered into the ruggedportions 31 a, 32 a of the comb tooth shape on the side of the firstholders 23, 24 to a predetermined depth, the joint end surface S1 of thesecond rubber sheet strip S being held by the holder portions 45, 46 onthe side of the second holders 41, 42 is pressured on and contacted withthe joint end surface S1 of the first rubber sheet strip S being held bythe holder portions 31, 32 on the side of the first holders 23, 24.

The stroke end of the second cylinder actuators 47, 48 has been set togive the both rubber sheet strip S a predetermined (e.g., one millimeteror so) pressuring allowance (ΔL). That is, the second holders 45, 46 arepartly overlapped respectively with the first holders 23, 24 so that therugged portions 45 a, 46 a of the comb tooth shape on the second holders45, 46 are complementarily meshed with the rugged portions 31 a, 32 a ofthe comb tooth shape on the first holders 23, 24 to a predetermineddepth of L1+ΔL. Thus, both rubber sheet strip S are pressured on eachother through the distance of the predetermined pressuring allowance(ΔL), and thus, the joint end surfaces S1 can be pressure-contacted witheach other with a strong pressure force in the state that the joint endportions of the both rubber sheet strips S are being held steadily,whereby the both rubber sheet strips S can be jointed reliably.

Because the second holders 41, 42 can respectively overlap with thefirst holders 23, 24 through the mutual meshing between the comb-toothshape rugged portions 31 a, 32 a and the comb-tooth shape ruggedportions 45 a, 46 a, it becomes possible to pressure-contact the jointend surfaces S1 of the both rubber sheet strips S with the strongpressuring force with the respective joint end portions of the bothrubber sheet strips S being steadily held by the respective holderportions 31, 32, 45, 46 of the first and second holders 23, 24, 41, 42.Accordingly, the joint end portions can be prevented from having anybulge thereon, and the flatness at the joint end portions can beimproved. Further, since any bulge does not occur, it becomesunnecessary to roll or smoothen the bulge portion with heat beingapplied to the rubber sheet strips S, so that the rubber sheet strips Scan be kept uniform in quality without being degenerated.

In this manner, the second cylinder actuators 47, 48 are operated totheir stroke ends, and the joint end surfaces S1 of the both rubbersheet strips S are pressure-contacted to be jointed with each other.Then, the third holders 55, 56 are moved by the third cylinder actuators57, 58 to come close to each other, whereby the jointed rubber sheetbatch S can be held at the right side portion of the first rubber sheetstrip S. At the same time, the first cylinder actuators 29, 30 areoperated, whereby the first holders 23, 24 and the second holders 41, 42are vertically moved to open while being guided along the linear guides25, 26 in the Z-axis direction, thereby to release the rubber sheetbatch S from the holding thereby.

Upon the releasing of the rubber sheet batch S from the holding by thefirst holders 23, 24 and the second holders 41, 42, the electric motor63 is operated to retract the third holders 55, 56 together with themovable table 52 by a stroke (LA) corresponding to the width dimensionof the rubber sheet piece S in the Y-axis direction. Thus, since therubber sheet batch S being held by the third holders 55, 56 is retractedby the width dimension (LA) of the rubber sheet piece S in the Y-axisdirection as shown in FIG. 9, it results that a new or next joint endsurface S1 of the rubber sheet batch S is positioned to the positionwhere it recedes by the slight amount L1 in the Y-axis direction fromthe end surface of the comb-tooth shape rugged portions 31 a, 32 a onthe first holders 23, 24.

When a third rubber sheet strip S is then supplied between the secondholders 41 and 42 in the same manner as the foregoing operation, thethird rubber sheet strip S is held by the second holders 41, 42, and atthe same time, the rubber sheet batch S composed of the plural jointedrubber sheet strips S is held by the first holders 23, 24. In thisstate, the second holders 41, 42 are moved toward the first holders 23,24 in the Y-axis direction, whereby in the same manner as describedabove, the joint end surface S1 of the third rubber sheet strip S ispressure-contacted with the joint end surface S1 of the rubber sheetbatch S thereby to joint both of them together.

During the jointing step of the rubber sheet strips S, the movable table52 is advanced by the operation of the electric motor 63 by the strokecorresponding to the width dimension LA of the rubber sheet strip S inthe Y-axis direction to feed the third holders 55, 56 to the positionshown in FIG. 8 by the predetermined amount (LA) relative to the rubbersheet batch S. It result from this that the third holders 55, 56 cancome to hold the rubber sheet batch S at the position which has apredetermined relation with the next joint end surface S1 of the rubbersheet batch S at all times. That is, by retracting the third holders 55,56 holding the rubber sheet batch S by the width dimension LA of therubber sheet strip S in the Y-axis direction, it becomes possible toposition the next joint end surface S1 of the rubber sheet batch S tothe predetermined position at all times.

By repetitively performing the foregoing operation, rubber sheet stripsS are successively jointed to one end surface of the rubber sheet batchS. When the rubber sheet batch S of a predetermined length (N×LA)corresponding to the body ply for one tire is manufactured by using therubber sheet strips S of a predetermined number (N), the rubber sheetbutch S (i.e., plane body ply sheet) is pulled by sheet drawing means(not shown) from between the third holders 55, 56. Thereafter, therubber sheet butch S is placed on a tray (not shown) and is transferredonto a tire shaping drum of another jointing apparatus (not shown) whichwill be described as a third embodiment of the present invention later.

It is to be noted that the body ply sheet S using the ribbon R may bemanufactured by using a ribbon which has been prepared in advance or maybe manufactured as the step to follow a step at which the ribbon R ismanufactured in a parallel time relation.

(Second Embodiment)

FIGS. 11 and 12 show a second embodiment according to the presentinvention, which exemplifies the manufacturing of sheets for belts ofautomotive tires with steel cords embedded therein.

A jointing apparatus 100 in this second embodiment uses a ribbon R of apredetermined width LA in which plural number of steel cords each madeby intertwisting plated wires are rubber-coated by being made to passthrough an unvulcanized composite rubber layer which is extruded from adie of a rubber extruding machine (not shown). The ribbon R sent outfrom a bobbin B is successively cut by cutting means 80 arranged at acutting station 1 st, to those strips S of a predetermined length LBwhich corresponds to a belt width determined by the specification of thetires to be manufactured. The cutting angle at which the ribbon R is cutcoincides with a belt angle which is inclined at a predetermined anglewith the cords C which are arranged in parallel with the longitudinaldirection of the ribbon R. Each rubber sheet strip S so cut is suppliedby supply means 70 to a butt joint station 2 st and is placed between apair of second holders 41, 42 (reference numeral 42 not shown) of secondholding means 22 to be held thereby. In this state, in the same manneras described in the foregoing first embodiment, the second holders 41,42 are moved relative to a pair of first holders 23, 24 (referencenumeral 24 not shown) of first holding means 21 in the Y-axis direction(in the upper-lower direction as viewed in FIG. 11) and are advanced toa position where comb-tooth shape rugged portions 45 a (46 a not shown)of the second holders 41, 42 are brought into meshing respectively withcomb-tooth shape rugged portions 31 a (32 a not shown) of the firstholders 23, 24. Thus, a joint end surface S1 of a rubber sheet strip Sbeing held by the second holders 41, 42 is pressure-contacted with ajoint end surface S1 of another rubber sheet strip S or a rubber sheetbatch S being held by the first holders 23, 24 thereby to join therubber sheet strip S with said another rubber sheet strip S or with therubber sheet batch S.

Third holders 55, 56 (reference numeral 56 not shown) holding thejointed rubber sheet batch S are movable in the Y-axis direction as wellas in an X-axis direction (the left-right direction as viewed in FIG.11) so that the rubber sheet batch S can be sent out along apredetermined angle inclined relative to the axes of the cords C.Therefore, each time a rubber sheet strip S is jointed, the thirdholders 55, 56 are moved by the width dimension LA of the rubber sheetstrip S in the Y-axis direction and at the same time, by a distancedepending on the inclination angle in the X-axis direction, whereby thejoint end surface S1 of the rubber sheet batch S can be positioned to apredetermined position at all times.

In this way, a plane belt sheet of the predetermined width for one tireis manufactured and is placed by sheet drawing means (not shown) on atray to be transferred to a shaping drum such as that referred to in thefollowing third embodiment of the present invention.

Each of the aforementioned embodiments describes the example whereinjointing is performed between the body ply sheets each having the fibercords embedded in the rubber sheet strip S or between the tire beltsheets each having the steel cords embedded in the rubber sheep strip S.However, the jointing apparatus and method according to the presentinvention is applicable to the manufacturing of a composite rubber sheetwhich is constituted by jointing rubber sheet strips each not having anycord embedded therein.

Of course, the specific constructions, support structures and operationsof the first holding means 21 and the second holding means 22 describedin the foregoing embodiments are not limited to those described in theforegoing embodiments and may take various forms without departing fromthe gist of the present invention.

As described hereinabove, in the foregoing embodiments, since the holderportions 31, 32, 45, 46 which are able to overlap to mesh with eachother are provided on the mutually facing surfaces of the first andsecond holding means 21, 22 for respectively holding the joint endportions of the two rubber sheets S to be jointed with each other, thejointing of the joint end surfaces S1 with each other can be realizedwith the joint end portions of the two rubber sheets S being held overthe entire parts thereof. Thus, even when the both rubber sheets S arepressure-joined with a strong pressuring force, any bulge can beprevented from occurring on the jointed portion. Therefore, it can berealized to easily manufacture rubber sheet blanks which are uniform inthickness and excellent in flatness. In addition, because no heat isapplied to the rubber sheets S, the same do not deteriorate in quality,so that it can be realized to easily obtain the rubber sheet blankswhich are uniform also in quality.

In the foregoing embodiments, since the apparatus is constructed tojoint the end surfaces S1 of the two rubber sheets S by allowing theholder portions 31, 32, 45, 46 to overlap with each other throughcomplementary meshing of the rugged portions 31 a, 32 a, 45 a, 46 a eachtaking the comb tooth shape, it can be realized to pressure-contact thejoint end surfaces S1 of the rubber sheets S steadily and to improve thejointing accuracy.

In the foregoing embodiments, since the wave claws 31 b, 32 b, 45 b, 46b are formed on the respective surfaces of the holder portions 31, 32,45, 46 which contact with the rubber sheets S, to bite the rubber sheetsS, it becomes possible to joint the rubber sheets S securely with astrong pressure force.

In the foregoing embodiments, since the relative moving amount given bythe operating means (i.e., the second cylinder actuators) 47, 48 betweenthe first and second holding means 21, 22 is set to give thepredetermined pressuring allowance (ΔL) between the two rubber sheets Sbeing respectively held by the first and second holding means 21, 22, itbecomes possible to heighten the jointing strength of the rubber sheetsS nevertheless any bulge hardly occurs at the joint end portions of therubber sheets S.

In the foregoing embodiments, since the holder portions 31, 32, 45, 46which are able to overlap to mesh with each other are respectivelyprovided on the mutually facing surfaces of the first and second holders23, 24, 41, 42, it becomes possible to pressure-contact the joint endsurfaces S1 with each other with the two rubber sheets S being held overthe entire parts of the joint end portions thereof, and hence, even whenthe both rubber sheets S are pressure-joined with a strong pressuringforce, any bulge can be prevented from occurring on the joint endportions. In addition, the third holders 55, 56 for holding the rubbersheet S delivered to and from the first holders 23, 24 are fed by thepredetermined amount LA whenever fed, it becomes possible to position anew or next joint end surface S1 of the jointed rubber sheet S to whichanother rubber sheet S is to be jointed, to the predetermined positionat all times. Therefore, the jointing of the rubber sheets S can beperformed efficiently only by holding a newly supplied rubber sheetstrip S by the second holders 41, 42 and then by moving the secondholders 41, 42 relative to the first holders 23, 24.

In the foregoing embodiments, the first holders 23, 24 holding the jointend portion of one of the two rubber sheets S and the second holders 41,42 holding the joint end portion of the other rubber sheet S arerelatively moved to the position where they partly overlap with eachother, to joint the both rubber sheets S, and the jointed rubber sheet Sis fed by the predetermined amount LA relative to the first holders 23,24 to position a new or next joint end surface S1 of the jointed rubbersheet S to which another rubber sheet S is to be jointed, to thepredetermined position at all times. Thus, even when the both rubbersheets S are pressure-joined with a strong pressuring force, any bulgecan be prevented from occurring at the joint end portions. This makes itunnecessary to perform a leveling or smoothening step of rolling orleveling any bulge which would otherwise be formed on the rubber sheet Safter the jointing step. Accordingly, it can be realized to the jointingmethod capable of efficiently manufacturing the rubber sheet blankswhich are uniform in thickness and excellent in flatness.

(Third Embodiment)

Hereafter, description will be made regarding a rubber sheet jointingapparatus and method which is practiced for jointing the opposite endsof a rubber sheet 115, that is, for jointing the first and last or N-thrubber sheet strips of the rubber sheet S manufactured in any of theforegoing first and second embodiments. Although the rubber sheetjointing apparatus and method in the third embodiment according to thepresent invention is preferably applied to the manufacturing of bodyplies for automotive tires, the apparatus and method is not limited onlyto any particular filed of application.

Referring now to FIG. 13, there is schematically shown a manufacturingapparatus 110 for cylindrical or round rubber sheet blanks such as bodyor carcass plies for automotive tires. The terms “carcass ply” and “bodyply” are interchangeably used in the same meaning herein. The rubbersheet 115 is of a plane form and will be called “plane rubber sheet 115”occasionally in the following description.

The manufacturing apparatus 110 is composed primarily of a rubber sheettransfer device 111 for transferring a cord-reinforced rubber sheet 115which is to become a carcass or body ply of a tire, a rubber sheetwinding device 112 for winding the rubber sheet 115 on thecircumferential surface of a shaping drum 117, and a rubber sheetjointing device 113 for jointing the circumferential opposite ends ofthe rubber sheet 115.

As shown in FIG. 14, the rubber sheet transfer device 111 is providedwith a transfer table 123 movably supported on a pair of rails 122 and asupport table 124 vertically movably supported on the transfer table123, and the rubber sheet 115 is placed on the support table 124. In thepresent embodiment, it is assumed that the rubber sheet 115 is made bycutting an unvulcanized rubber ribbon which has been scrolled around abobbin (not shown) in advance, to those sheets of a predetermined lengthdetermined in dependence on the kind, size and the like of the tires tobe manufactured. However, in a modified form, the rubber sheet 115 maybe made by joining plural elongated rubber sheet strips one afteranother at their side surfaces parallel to the lengthwise direction ofthe rubber sheet strips, as described in the foregoing embodiments.

The rubber sheet winding device 112 rotatably supports a shaping drum117 whose construction will be referred to later in detail. The supporttable 124 with the rubber sheet 115 placed thereon is transferredtogether with the transfer table 123, and when one end (i.e., a windingstart end portion) 115 a is positioned under the axis of the shapingdrum 117, the support table 124 is moved upward by an elevation cylinderactuators 125. Thus, the winding start end portion 115 a of the rubbersheet 115 is brought into contact with the circumferential surface ofthe shaping drum 117. In this state, the shaping drum 117 is rotated, insynchronous relation with which the rubber sheet transfer device 111 isfurther moved forward. As a consequence, the rubber sheet 115 is woundas one turn on the circumferential surface of the shaping drum 117,wherein the winding start end portion 115 a of the rubber sheet 115becomes to face a winding terminal end portion 115 b thereof with aslight clearance therebetween.

Next, the structure of the shaping drum 117 will be described withreference to FIG. 17. The shaping drum 117 is provided with a shaftsleeve 130 and a pair of discs 131 a, 131 b secured to the axialopposite ends of the shaft sleeve 130. The shaft sleeve 30 is rotatablycarried on the rubber sheet winding device 112 and is rotatable byrotation drive means (not shown) through a predetermined angle.

A plurality of segments 133 arranged at an equiangular distancecircumferentially of the shaft sleeve 130 are carried between the pairof discs 131 a, 131 b to be movable in radial directions. Brackets 134a, 134 b are secured at both axial end portions on the internal surfaceof each segment 133 and are guided and supported on the axially insidesurfaces of the respective discs 131 a, 131 b to be movable radially. Adrum diameter altering member 136 of a generally cylindrical shape isfit on the external surface of the shaft sleeve 130 to be axiallymovable relative thereto, and slant cam members 137 a, 137 b inclined ata predetermined angle with the axis of the drum diameter altering member136 are formed at both axial end portions of the circumferential surfaceof the drum diameter altering member 136. The brackets 134 a, 134 bwhich are attached to the internal surface of each segment 133 areguided along the slant cam members 137 a, 137 b through guide members138 a, 138 b, respectively.

An adjuster shaft 140 is rotatably supported inside the shaft sleeve 130to pass through the same and is rotatable by rotation drive means (notshown). Inside the shaft sleeve 130, a ball screw shaft 141 is rotatablysupported and is connected to an inner end of the adjuster shaft 140.The ball screw shaft 141 has screw-engaged therewith a nut 142, which isconnected with the drum diameter altering member 136 through aconnection plate 143.

With the construction as aforementioned, when the ball screw shaft 141is rotated upon rotation of the adjuster shaft 140, the drum diameteraltering member 136 is axially moved through the nut 142 and theconnection plate 143. This causes the respective segments 133 tosynchronously move in radial directions intersecting the axis of theshaft sleeve 130, whereby adjustment is performed to alter the drumdiameter of the shaping drum 117 constituted by the gathering of theplural segments 133.

In order to cover or fill the space which would otherwise be madebetween every two adjoining segments 133 in connection with thealteration adjustment in the drum diameter of the shaping drum 117,rugged portions 133 a, 133 b of a predetermined depth as shown in FIG.18 are formed respectively at the both end portions in thecircumferential direction of each segment 133, and the adjoiningsegments 133 can complementarily overlap with each other through themeshing of the rugged portions 133 a, 133 b. Thus, the external surfaceof the shaping drum 117 can be formed to continue in the circumferentialdirection.

Of the foregoing plural segments 133 arranged circumferentially, a pairof jointing segments 145, 146 which correspond to seams at thecircumferential opposite end portions of the rubber sheet 115respectively have at their facing end surfaces rugged portions 145 a,146 a of a comb tooth shape formed to a predetermined depth, and theserugged portions 145 a, 146 a of the comb tooth shape can complementarilymesh with each other. Thus, the jointing segments 145, 146 have formedat their external surfaces holder portions 145 a, 145 b which arecapable of holding the circumferential opposite end portions of therubber sheet 115 at convex portions of the comb tooth shape. In thisway, by overlapping the pair of jointing segments 145, 146 with eachother through the complementary meshing between the comb-tooth shaperugged portions 145 a, 146 a, it becomes possible to joint thecircumferential opposite end portions of the rubber sheet 115 with eachother with the jointing segments 145, 146 holding the entire parts ofthe both extreme end portions in the circumferential direction of therubber sheet 115.

As shown in FIG. 21, the holder portions 145 a, 145 b have formedthereon wave claws 145 c, 146 c such as, e.g., saw tooth claws of aminute height which bite the surfaces at the circumferential oppositeend portions of the rubber sheet 115 so that the surfaces at thecircumferential opposite end portions do not retract relative to theholder portions 145 a, 145 b during the jointing operation.

Each of the pair of jointing segments 145, 146 protrudes engaging pins147, 148 from the axial opposite end portions thereof. The distance (L2)in a tangential direction of the shaping drum 117 (e.g., in thecircumferential direction) between the engaging pins 147, 148 are variedby the movements of the segments 145, 146 in the radial directions, thatis, by the increase or decrease of the drum diameter of the shaping drum117. Thus, when the drum diameter is decreased, the circumferentialopposite end portions of the rubber sheet 15 which portions are beingheld by the jointing segments 145, 146 are brought into contact witheach other.

Next, with reference to FIGS. 15, 16 and 19, description will be maderegarding the construction of the rubber sheet jointing device 113 forjointing the circumferential opposite end portions of the rubber sheet115 being wound around the shaping drum 117. The rubber sheet jointingdevice 113 is arranged over the shaping drum 117, and a fixed frame 150thereof guides a vertically movable member 152 through a plurality ofguide bars 151 in a vertical direction (in a radial direction of theshaping drum 117). The vertically movable member 152 is movable by apressuring cylinder actuator 153 mounted on the fixed frame 150 towardand away from the shaping drum 117. A pair of guide rails 155respectively constituting linear guides are mounted on an end (lowerend) of the vertically movable member 152 to extend tangentially of theshaping drum 117, and two horizontally movable members 157, 158 aremounted on the guide rails 155 through guide blocks 159, 160 to comeclose to or away from each other in a tangential direction (thecircumferential direction) of the shaping drum 117.

That is, the two horizontally movable members 157, 158 are arranged toface with each other with the vertical axis (L0) (refer to FIG. 21)therebetween and have the length corresponding approximately to thelength of the shaping drum 117 in the axial direction of the same. Asbest shown in FIG. 19, rugged portions 157 a, 158 a each taking a combtooth shape are formed on the mutually facing end surfaces of therespective horizontally movable members 157, 158 to a predetermineddepth and are able to complementarily mesh with each other. Thus,pressuring portions 157 b, 158 b are formed on the lower surfaces of thehorizontally movable members 157, 158 for pressuring the circumferentialopposite end portions of the rubber sheet 115 by the rugged portions 157a, 158 a of the comb tooth shape over the entire lengths thereof. Inthis way, by partly overlapping the pair of horizontally movable members157, 158 through the complementary meshing between the rugged portions157 a, 158 a of the comb tooth shape, it becomes possible to joint thecircumferential opposite end surfaces of the rubber sheet 115 with thepressuring portions 157 b, 158 b of the horizontally movable members157, 158 pressuring the circumferential opposite end edge portions ofthe rubber sheet 115 downward.

As shown in FIG. 21 in detail, the pressuring portions 157 b, 158 b haveformed thereon wave claws 157 c, 158 c such as, e.g., saw tooth claws ofa minute height which bite the external surfaces at the circumferentialopposite end portions of the rubber sheet 115 so that thecircumferential opposite end portions do not retract relative to thepressuring portions 157 b, 158 b to separate from each other during thejointing operation.

As shown in FIGS. 19 and 20, the horizontally movable members 157, 158respectively protrude contact pieces 161, 162 toward the verticallymovable member 152 and are each urged by the resilient force of acompression spring 164 arranged between itself and a bracket 163 securedto the vertically movable member 152, to come into contact with a stop165 or 166 associated therewith. Usually, the horizontally movablemembers 157, 158 are held at respective positions where the contractpieces 161, 162 are kept in abutment with the stops 165, 166,respectively. Thus, the movable members 157, 158 are prevented fromrelatively moving in a direction to go away from each other beyond thestops 165, 166, but are allowed to relatively move in the otherdirection to come close to each other (in the direction against theresilient force of the compression springs 163).

Engaging blocks 167, 168 are attached to the opposite ends in thelengthwise direction of the horizontally movable members 157, 158 andhave formed thereon engaging grooves 167 a, 168 a (refer to FIG. 21)opening downward, respectively. The engaging grooves 167 a, 168 a of theengaging blocks 167, 168 are brought by the downward advance movement ofthe vertically movable member 152 into engagement with the engaging pins147, 148 protruding from the pair of jointing segments 145, 146,respectively. The respective horizontally movable members 157, 158 aresynchronously moved to come close to each other when the contraction inthe drum diameter of the shaping drum 117 causes the pair of jointingsegments 145, 146 to advanced toward each other in the tangentialdirection of the shaping drum 117 with the engaging grooves 167 a, 168 abeing engaged with the engaging pins 147, 148, respectively.

The foregoing engaging blocks 167, 168 and the engaging pins 147, 148constitute synchronous moving means recited in the claimed invention,and the synchronous moving means is able to move the holder portions 145a, 145 b formed in the jointing segments 145, 146 and the pressuringportions 157 b, 158 b formed on the horizontally movable members 157,158 in a synchronous relation with each other. The construction of thesynchronous moving means is not limited to that described above. Forexample, the engaging pins 147, 148 may be provided on the sides of thehorizontally movable members 157, 158, whereas the engaging blocks 167,168 may be provided on the sides of the jointing segments 145, 146.

(Operation)

The operation of the third embodiment as constructed above will bedescribed hereinafter. First of all, description will be made regardingthe operation for winding the rubber sheet 115 on the circumferentialsurface of the shaping drum 117. It is now assumed that prior to thewinding operation of the rubber sheet 115, the shaping drum 117 is keptin an expansion state with the pair of the jointing segments 145, 146being positioned to an angular position where they are placed beneaththe axis of the shaping drum 117.

When a rubber sheet 115 having been cut to the predetermined lengthdetermined in dependence on the kind, dimension and the like of thetires to be manufactured is placed on the support table 124 of therubber sheet transfer device 111, the transfer table 123 supporting thesupport table 124 thereon is transferred by the transfer cylinderactuator (not shown) along the rails 122 toward the right as viewed inFIG. 13, and one end (the winding start end portion) 115 a of the rubbersheet 115 is positioned to a position which corresponds to one of thejointing segments 145, 146 positioned beneath the shaping drum 117.

Thereafter, the support table 124 of the rubber sheet transfer device111 is moved upward by the elevation cylinder actuators 125, and thewinding start end portion 115 a of the rubber sheet 115 is brought intocontact with the circumferential surface (with one of the pair ofjointing segments 145, 146) of the shaping drum 117 and is made by clingholding means (not shown) to cling to the circumferential surface of theshaping drum 117. In this state, the transfer table 123 supporting thesupport table 124 thereon is further transferred toward the right asviewed in FIG. 13, simultaneously with which the shaping drum 117 isrotated by the rubber sheet winding device 112. This causes the rubbersheet 115 to be wound as approximately one turn around thecircumferential surface of the shaping drum 117, whereby in the samemanner as is done with the winding start end portion 115 a, the windingterminal end portion 115 b of the rubber sheet 115 is made by the clingholding means (not shown) to cling to the circumferential surface (tothe other of the pair of jointing segments 145, 146) of the shaping drum117.

In this way, the seams being respectively the winding start end portion115 a and the winding terminal end portion 115 b of the rubber sheet 115are placed on the circumferential surface of the shaping drum 117, thatis, between the jointing segments 145, 146 to face each other with aslight clearance therebetween in the circumferential or tangentialdirection of the shaping drum 117. Then, the shaping drum 117 is rotatedby the rubber sheet winding device 112 through about 180 degrees toposition the seams of the rubber sheet 115 to an upward angular positionwhere the seams face the rubber sheet jointing device 113.

In this state, the vertically movable member 152 of the rubber sheetjointing device 113 is moved down by the pressuring cylinder actuator153, whereby the engaging grooves 167 a, 168 a of the engaging blocks167, 168 attached to the horizontally movable members 157, 158 arebrought into engagements respectively with the engaging pins 147, 148and whereby the pressuring portions 157 b, 158 b of the horizontallymovable members 157, 158 are pressured by the thrust force of thepressuring cylinder actuator 153 respectively upon the circumferentialopposite end portions of the rubber sheet 115. Thus, the circumferentialopposite end portions of the rubber sheet 115 are pinched from radialinside and outside by the holding portions 145 b, 146 b of the jointingsegments 145, 146 and the pressuring portions 157 b, 158 b of thehorizontally movable members 157, 158. The pinching of the rubber sheet115 by the jointing segments 145, 146 and the horizontally movablemembers 157, 158 is kept by a later follow motion of the pressuringcylinder actuator 153 while the drum diameter of the shaping drum 117 isdecreased.

Subsequently, the adjuster shaft 140 of the shaping drum 117 is rotatedby the rotation drive means (not shown). Upon rotation of the adjustershaft 40, the ball screw shaft 141 is rotated to axially move the drumdiameter altering member 136 toward the right as viewed in FIG. 17through the nut 142 and the connection plate 143. Thus, by the camaction of the cam members 137 a, 137 b, the plurality ofcircumferentially arranged segments 133 including the jointing segments145, 146 are moved radially inward along the guide members 135 a, 135 bto decrease the drum diameter of the shaping drum 117.

With the decrease in the drum diameter of the shaping drum 117, the pairof jointing segments 145, 146 which correspond to the seams at thecircumferential end portions of the rubber sheet 115 are moved inward inthe radial direction as they are moved in the tangential direction (inthe circumferential direction) of the shaping drum 117 perpendicularthereto. This causes the engaging pins 147, 148 protruding from the pairof jointing segments 145, 146 to decrease the distance (L2) (refer toFIG. 21) in the tangential direction with the decrease in the drumdiameter of the shaping drum 117. Thus, the pair of horizontally movablemembers 157, 158 which engage the engaging pins 147, 148 through theengaging blocks 167, 168 are also relatively moved to come close to eachother synchronously with the movements in the tangential direction (thecircumferential direction) of the jointing segments 145, 146.

Since in this way, the holder portions 145 b, 146 b of the jointingsegments 145, 146 and the pressuring portions 157 b, 158 b of thehorizontally movable members 157, 158 which cooperate to pinch thecircumferential opposite end portions of the rubber sheet 115 are movedto come close to each other with the decrease in the drum diameter ofthe shaping drum 117, the circumferential opposite end portions (thewinding start end portion 115 a and the winding terminal end portion 115b) of the rubber sheet 115 are caused to come close to each other andfinally, are strongly pressured on each other at their end surfaces tobe butt-jointed.

At this time, since the jointing segments 145, 146 having the holderportions 145 b, 146 b formed thereon and the horizontally movablemembers 157, 158 having the pressuring portions 157 b, 158 b formedthereon which cooperate to pinch the rubber sheet 115 are overlapped attheir rugged portions 145 a, 146 a, 157 a, 158 a of the comb toothshape, the circumferential opposite end surfaces of the rubber sheet 115can be pressure-jointed through the predetermined pressuring allowancewhile the circumferential opposite end portions of the rubber sheet 115are fully pinched over the entire parts thereof. The wave claws 145 c146 c, 157 c, 158 c formed on the holder portions 145 b, 146 b and thepressuring portions 157 b, 158 b prevent the rubber sheet 115 fromslipping during the jointing operation.

As a consequence, even when the circumferential opposite end portions ofthe rubber sheet 115 are pressure-jointed with a strong pressuringforce, the pressure-jointed portion does not have any bulge thereon andcan be improved in flatness. Further, since any bulge does not occur, itbecomes unnecessary to roll or level any bulged portion which wouldotherwise occur, with the rubber sheet 115 being heated as is done inthe prior art, and therefore, the rubber sheet 115 can be kept uniformin quality without being degenerated by the heat.

Upon completion of the step of jointing the circumferential opposite endportions of the rubber sheet 115 in this manner, the circumferentialsurface of the rubber sheet 115 now taking a round form is held by avacuum pad (not shown) as described in, e.g., Japanese Published,Unexamined Patent Application No. 2001-138404, in which state the vacuumpad is then moved axially of the shaping drum 117 to remove the roundrubber sheet 115 from the circumferential surface of the shaping drum117. Thereafter, the round rubber sheet 115 removed from thecircumferential surface of the shaping drum 117 is transferred to a tireassembling station (not shown) next to the manufacturing apparatus 110.

In the foregoing third embodiment, by the contraction in the drumdiameter of the shaping drum 117, the pair of jointing segments 145, 146with the holder portions 145 b, 146 b formed thereon are moved radiallyof the shaping drum 117 as they are moved in the tangential direction ofthe shaping drum 117, and the circumferential opposite end portions ofthe rubber sheet 115 are pressure-jointed by the utilization of therelative movement of the holder portions 145 b, 146 b in the tangentialdirection. However, where it is desired that the relative movementbetween the holder portions 145 b, 146 b in the tangential direction ofthe shaping drum 117 be much longer, there may be employed individualrelative moving means which are provided for effecting the relativemovement between the holder portions 145 b, 146 b independently of thejointing segments 145, 146.

As described above, in the aforementioned third embodiment, the meshingportions which are able overlap to mesh with each other are formed onthe holder portions 145 b, 146 b which are movable radially of theshaping drum 117, as well as on the pressuring portions 157 b, 158 bwhich are provided on the vertically movable member 152 to be relativelymovable in the tangential direction of the shaping drum 117 forpressuring the circumferential opposite end portions of the rubber sheet115 respectively on the holder portions 145 b, 146 b. Further, thesynchronous moving means 167, 168, 147, 148 is provided for relativelymoving the holder portions 145 b, 146 b and the pressuring portions 157b, 158 b in the synchronous relation in the tangential direction of theshaping drum 117. Thus, relative movements in the synchronous relationare performed between the holder portions 145 b, 146 b as well asbetween the pressuring portions 157 b, 158 b with all the parts of thecircumferential opposite end portions of the rubber sheet 115 beingpinched by the holder portions 145 b, 146 b and the pressuring portions157 b, 158 b. Accordingly, it can be realized to obtain the rubber sheetjointing apparatus which is capable of jointing the circumferentialopposite end portions of the rubber sheet 115 easily and reliablywithout having any bulge at the jointed portion.

Also in the aforementioned third embodiment, since each of the holderportions 145 b, 146 b and the pressuring portions 157 b, 158 b has thewave claws 145 c, 146 c, 157 c, 158 c which are formed at the contactsurface with the rubber sheet 115 for biting the rubber sheet 115, it ispossible to securely joint the circumferential opposite end portionswith a strong pressuring force.

Also in the aforementioned third embodiment, the synchronous movingmeans is composed of the engaging pins 147, 148 respectively provided onthe holder portions 145 b, 146 b and the engaging members 167, 168respectively provided on the pressuring portions 157 b, 158 b andengageable by the advance movement of the vertically movable member 152respectively with the engaging pins 147, 148. Thus, by the advance orretraction movement of the vertically movable member 152, the engagingmembers 167, 168 are brought into engagements with the engaging pins147, 148, so that the synchronous moving means can be simplified inconstruction.

Further, in the aforementioned third embodiment, the circumferentialopposite end portions of the rubber sheet 115 are pinched between theholder portions 145 b, 146 b which are provided on the shaping drum 117to mesh with each other in the partly overlapping state and thepressuring portions 157 b, 158 b which are provided on the verticallymovable member 152 to mesh with each other in the partly overlappingstate, and with the circumferential opposite end portions being pinched,the relative movement in the tangential direction of the shaping drum117 is performed between the holder portions 145 b, 146 b as well asbetween the pressuring portions 157 b, 158 b, whereby thecircumferential opposite end portions of the rubber sheet 115 arebutt-jointed with each other. Thus, it can be realized to pressure-jointthe circumferential opposite end portions of the rubber sheet 115 witheach other with the circumferential opposite end portions being fullyheld over the entire parts thereof. Therefore, even when thecircumferential opposite end portions are jointed with a strongpressuring force, the jointed portion can be prevented from having anybulge thereat. Since this advantageously makes unnecessary anysmoothening step which would otherwise be required for rolling orleveling any such bulge after the jointing of the rubber sheet 115, itbecomes possible to easily obtain the rubber sheet jointing methodcapable of efficiently manufacturing the rubber sheet 115 which isuniform in thickness, excellent in flatness and also uniform in quality.

The specific constructions of the rubber sheet jointing device 113 andthe shaping drum 117 described in the foregoing third embodiment areonly to show an example suitable to implementing the present invention.Of course, the present invention is not limited to the constructions asdescribed above and may take any of various forms without departing fromthe gist of the present invention.

(Fourth Embodiment)

FIGS. 22 through 26 show the fourth embodiment according to the presentinvention, which is designed to manufacture an endless band bybutt-jointing a forward end portion of the rubber sheet batch S, whichis manufactured as described in the foregoing first embodiment to havethe predetermined length corresponding to one tire, with a rear endportion of the rubber sheet batch S.

The fourth embodiment is further provided with a rubber sheet batchturning-up means 81 for turning up the rubber sheet batch S to aposition which enables the second holding means 22 to hold the forwardend portion of the rubber sheet batch S in such a way that the rubbersheet batch turning-up means 81 grips the forward end of the rubbersheet batch S which is sent out by the predetermine amount from betweenthe third holders 55, 56 of the feeding means 54 and then moves theforward end portion of the rubber sheet batch S step by step along aloop locus. The fourth embodiment differs from the foregoing firstembodiment in the respect that it is provided with the rubber sheetbatch turning-up means 81. The fourth embodiment and the foregoing firstembodiment take the same construction and perform the same operation inmanufacturing the rubber sheet batch S of the predetermined lengthcorresponding to one tire. Therefore, also with reference to somefigures for the first embodiment, the following description will beaddressed mainly to the differences from the first embodiment. In FIGS.22 and 23, components identical to those in the first embodiment aregiven the same reference numerals as used in the first embodiment, andthe description of the identical components will be omitted for the sakeof brevity.

In the fourth embodiment wherein the endless band is manufactured, it isnecessary to take the manufactured band away from the rubber sheetjointing apparatus 10 described in the foregoing first embodiment.Therefore, in the fourth embodiment, one of the pair of support pillars13, 14 (i.e., the support pillar 13) upstanding in the rubber sheetjointing apparatus 10 as shown in FIG. 3 is removed, and the rubbersheet jointing apparatus 10 is supported by the other support pillar 14only in a cantilever fashion (refer to FIG. 22), in which respect thefourth embodiment is also different from the first embodiment.

Hereafter, the fourth embodiment will be described with reference toFIGS. 22 through 26 taking an example wherein a material handling robotis utilized as the rubber sheet batch turning-up means 81. The robot hasa robot arm 83, which is provided with a pair of hands 85 and 86operable to open and close, as shown in FIG. 25. These hands 85, 86 areoperable to grip the forward end portion of the rubber sheet batch Swhich is sent out from the pair of third holders 55, 56. At this time,as shown in FIG. 24, the hands 85, 86 grip a portion of the rubber sheetbatch S retracted from the end face S11 of the forward end portion forhandover or delivery between themselves and the second holders 41, 42.

The robot arm 83 has the freedom of at least three axes in movement,wherein it is movable in the left-right direction (Y-axis direction) andthe vertical direction (Z-axis direction) as viewed in FIG. 23 and isrotatable about a 9-axis perpendicular to the Y and Z-axes. Thus, withsimultaneous controls of the robot arm 83 along the three axes, theforward end portion of the rubber sheet batch S gripped by the hands 85,86 is turned up to a position to face the rear end portion of the rubbersheet batch S while being controllably moved along the loop locus LLshown in FIG. 26 step by step, each step corresponding to the widthdimension LA of the rubber sheet strip shown in FIG. 10.

Further, in the fourth embodiment, as described in the foregoing firstembodiment, the rubber sheet strips S are successively supplied by thesupply means 70 to the butt joint station 2 st and are jointed one afteranother to manufacture the rubber sheet batch S. When the forward endportion of the rubber sheet batch S (i.e., the first rubber sheet strip)is protruded by a predetermined amount from the third holders 55, 56,the hands 85, 86 of the robot arm 83 grip the forward end portion of therubber sheet batch S, as shown in FIGS. 22 and 24. With the grippingstate being kept, the robot arm 83 under the simultaneous controls ofthe three axes is controllably moved along the loop locus LL shown inFIG. 26 by the step or distance corresponding to the width dimension LAof each rubber sheet strip in turn in the direction of the arrowindicated in FIG. 26 each time the rubber sheet batch S is sent out bythe predetermined distance upon completion of the jointing of eachrubber sheet strip.

When the rubber sheet batch S of the predetermined length correspondingto one tire is manufactured in this way, the robot arm 83 reaches theposition shown in FIG. 26, whereby the forward end portion of the rubbersheet batch S gripped by the hands 85, 86 of the robot arm 83 ispositioned to a position where it can be held by the second holdingmeans 22. That is, as shown in FIG. 4, the end surface 511 of theforward end portion of the rubber sheet batch S comes to take theposition which is between the second holders 41 and 42 and which isretracted by the slight amount L1 from the end surfaces of the ruggedportions 45 a, 46 a of the comb tooth shape.

In this state, in the same manner as described in the first embodiment,each pair of the first holders 23, 24 and the second holders 41, 42 arevertically moved by the operations of the first cylinder actuators 29,30 to come close to each other, whereby the rear end portion of therubber sheet batch S being held by the third holders 55, 56 is held bythe first holders 23, 24 while the forward end portion of the rubbersheet batch S being held by the hands 85, 86 of the robot arm 83 is heldby the second holders 41, 42. Therefore, as indicated by thetwo-dot-chain line in FIG. 4, the rubber sheet batch S has its rear endsurface held by the holder portions 31, 32 at the position retracted bythe distance L1 from the end surfaces of the rugged portions 31 a, 32 aof the comb tooth shape and also has its forward end surface held by theholder portions 45, 46 at the position retracted by the distance L1 fromthe end surfaces of the rugged portions 45 a, 46 a of the comb toothshape.

Then, the second holders 41, 42 are moved by the operations of thesecond cylinder actuators 47, 48 toward the first holders 23, 24, andthe end surface S11 of the forward end portion of the rubber sheet batchS (i.e., the first rubber sheet strip) being held by the second holders41, 42 is pressured on the end surface S12 of the rear end portion ofthe rubber sheet batch S (i.e., the last jointed rubber sheet strip)being held by the first holders 23, 24 as the comb tooth shape ruggedportions 45 a, 46 a formed on the second holders 41, 42 arecomplementarily meshed with the comb tooth shape rugged portions 31 a,32 a formed on the first holders 23, 24, whereby the endless band ismanufactured with the first rubber sheet strip and the last jointedrubber sheet strip being jointed with each other.

The endless band manufactured in this way is taken out by a bandtaking-out means (not shown) in the X-axis direction (the left-rightdirection as viewed in FIG. 22) to be carried out of the rubber sheetjointing apparatus 10 and is transferred to a tire assembling step orapparatus (not shown).

According to the foregoing fourth embodiment, by the use of the rubbersheet jointing apparatus 10 similar to that described in the firstembodiment, it can be realized to manufacture the rubber sheet batch Sof the predetermined length from the plurality of rubber sheet strips Sand to continuously manufacture the endless band from the rubber sheetbatch S. Accordingly, it can be realized to manufacture the endlessbands suitable for use in tires efficiently by the use of thespace-saving equipment or facilities.

In particular, where the fourth embodiment is practiced, it becomesunnecessary to provide the rubber sheet jointing apparatus 110 as usedin the third embodiment for jointing the opposite ends of the rubbersheet 115 (i.e., the rubber sheet batch S in the fourth embodiment).Therefore, a tire production system including the rubber sheet jointingapparatus 10, the tire assembling apparatus and the like can besimplified in construction and reduced in scale, so that substantialachievements can be realized not only in reducing the cost formanufacturing the tire production system, but also in enhancing the tireproductivity as a result of the cycle time for tire production beingshortened.

Although the fourth embodiment has been described taking the examplewherein the robot is utilized in turning up the forward end portion ofthe rubber sheet batch S to the position to face the rear end portion ofthe rubber sheet batch S, the present invention is not necessarilylimited to utilizing the robot. For example, the fourth embodiment maybe modified to take a construction wherein gripper means for grippingthe forward end portion of the rubber sheet batch S is provided on amovable member which is movably guided along a loop guide member andwherein the movable member is moved along the guide member tocontrollably move the forward end portion of the rubber sheet batch Salong the loop locus.

Although the fourth embodiment has been described taking the examplewherein tire body plies are manufactured, it may be applied to themanufacturing of the belts of automotive tires with steel cords embeddedtherein as practiced in the foregoing second embodiment.

Obviously, numerous further modifications and variations of the presentinvention are possible in light of the above teachings. It is thereforeto be understood that within the scope of the appended claims, thepresent invention may be practiced otherwise than as specificallydescribed herein.

What is claimed is:
 1. A rubber sheet jointing apparatus wherein aplurality of rubber sheets are jointed by butt joint at opposite ends ofadjacent ones of the rubber sheets one after another to manufacture anelongated rubber sheet batch, and wherein opposite ends of the elongatedrubber sheet batch are jointed by butt joint with each other tomanufacture an endless band, the apparatus comprising: first holdingmeans for releasably holding a joint end portion of a first rubbersheet; second holding means provided movably relative to the firstholding means for releasably holding a joint end portion of a secondrubber sheet; operating means for pressure-contacting the joint endportion of the first rubber sheet and the joint end portion of thesecond rubber sheet respectively held by the first and second holdingmeans with each other by effecting relative movement between the firstand second holding means; and rubber sheet batch turning-up means formoving a forward end portion of the rubber sheet batch made by jointingthe plurality of rubber sheets, along a loop locus incrementally to turnup the forward end portion of the rubber sheet batch to a position whichenables the second holding means to hold the forward end portion of therubber sheet batch, wherein mutually facing surfaces of the first andsecond holding means are respectively provided with holder portionswhich are configured to overlap to mesh with each other.
 2. The rubbersheet jointing apparatus as set forth in claim 1, wherein the rubbersheet batch turning-up means is constituted by a robot having handsconfigured to grip the forward end portion of the rubber sheet batch,and wherein the robot is operable to move the forward end portion of therubber sheet batch incrementally along the loop locus.
 3. A rubber sheetjointing method wherein a plurality of rubber sheets are jointed by buttjoint at opposite ends of adjacent ones of the rubber sheets one afteranother to manufacture an elongated rubber sheet batch, and whereinopposite ends of the elongated rubber sheet batch are jointed by buttjoint with each other to manufacture an endless band, the methodcomprising: providing first and second holding devices which areconfigured to partly overlap to mesh with each other at mutually facingsurfaces thereof; making one of the first and second holding deviceshold a joint end portion of a first rubber sheet and making the other ofthe first and second holding devices hold a joint end portion of asecond rubber sheet; relatively moving the first and second holdingdevices to a position where the first holding device partly overlapswith the second holding device through a meshing engagement at themutually facing surfaces of the first and second holding devices, tojoint through pressuring contact an end surface of the joint end portionof the first rubber sheet being held by the first holding device with anend surface of the joint end portion of the second rubber sheet beingheld by the second holding device; moving a forward end portion of therubber sheet batch made by jointing the plurality of rubber sheets,incrementally along a loop locus to turn up the forward end portion ofthe rubber sheet batch to a position which enables the second holdingdevice to hold the forward end portion of the rubber sheet batch; andeffecting a relative movement between the second holding device holdingthe forward end portion of the rubber sheet batch and the first holdingdevice holding a rear end portion of the rubber sheet batch to aposition where the first and second holding devices partly overlap tomesh with each other at mutually facing surfaces thereof, to joint theopposite ends of the rubber sheet batch with each other.
 4. A rubbersheet jointing apparatus wherein a plurality of rubber sheets arejointed by butt joint at opposite ends of adjacent ones of the rubbersheets one after another to manufacture an elongated rubber sheet batch,and wherein opposite ends of the elongated rubber sheet batch arejointed by butt joint with each other to manufacture an endless band,the apparatus comprising: a first holding device to releasably hold ajoint end portion of a first rubber sheet; a second holding deviceprovided movably relative to the first holding device to releasably holda joint end portion of a second rubber sheet; an operating device topressure-contact the joint end portion of the first rubber sheet and thejoint end portion of the second rubber sheet respectively held by thefirst and second holding devices with each other by effecting relativemovement between the first and second holding devices; and a rubbersheet batch turning-up device to move a forward end portion of therubber sheet batch made by jointing the plurality of rubber sheets,along a loop locus incrementally to turn up the forward end portion ofthe rubber sheet batch to a position which enables the second holdingdevice to hold the forward end portion of the rubber sheet batch,wherein mutually facing surfaces of the first and second holding devicesare respectively provided with holder portions which are configured tooverlap to mesh with each other.
 5. The rubber sheet jointing apparatusas set forth in claim 4, wherein the rubber sheet batch turning-updevice is constituted by a robot having hands configured to grip theforward end portion of the rubber sheet batch and wherein the robot isoperable to move the forward end portion of the rubber sheet batchincrementally along the loop locus.